A 1-bit Digital Dynamically Biased Power Amplifier for Step Envelope Tracking Transmitters

This paper focuses and provides experimental data for a 1-bit step envelope tracking power amplifier as a suitable solution to enhance the average PAE for wide dynamic signals. The PA is based on an active core realized combining SiGe HBTs with different sizes, which shows a peak CW PAE around 38% for the state 1 and 42% for state 2 respectively when terminated with optimum terminations. The 1-bit step envelope tracking architecture and its digital predistortion algorithm were implemented in a laboratory test bench. The experimental characterization demonstrates the capability of the proposed system to provide a factor two of improvement in terms of average PAE, without limitation of other signal parameters. Experimental validation is reported for a 2 MHz multi-sine signal with 5.5 dB PAR at 2.074 GHz and for a 17 dBm output total power.